On 14.05.19 11:00, Cornelia Huck wrote:
> On Tue, 14 May 2019 10:56:43 +0200
> Christian Borntraeger <[email protected]> wrote:
>
>> On 14.05.19 10:50, David Hildenbrand wrote:
>
>>> Another idea for temporary handling: Simply only indicate 240 CPUs to
>>> the guest if the response does not fit into a page. Once we have that
>>> SCLP thingy, this will be fixed. Guest migration back and forth should
>>> work, as the VCPUs are fully functional (and initially always stopped),
>>> the guest will simply not be able to detect them via SCLP when booting
>>> up, and therefore not use them.
>>
>> Yes, that looks like a good temporary solution. In fact if the guest relies
>> on simply probing it could even make use of the additional CPUs. Its just
>> the sclp response that is limited to 240 (or make it 247?)
>
> Where did the 240 come from - extra spare room? If so, 247 would
> probably be all right?
>
+++ b/include/hw/s390x/sclp.h
@@ -133,6 +133,8 @@ typedef struct ReadInfo {
uint16_t highest_cpu;
uint8_t _reserved5[124 - 122]; /* 122-123 */
uint32_t hmfai;
+ uint8_t _reserved7[134 - 128]; /* 128-133 */
+ uint8_t fac134;
struct CPUEntry entries[0];
} QEMU_PACKED ReadInfo;
So we have "4096 - 135 + 1" memory. Each element is 16 bytes wide.
-> 246 CPUs fit.
--
Thanks,
David / dhildenb
